84 



DISEASES OF MUSCLES AND TENDONS. 



Beef measles is rather common in Germany, but rare in France, 

 Switzerland, and Italy. 



TRICHINIASIS-TRICHINOSIS. 



Trichinosis is a disease caused hy the entrance into the body of the 

 Trichina spiralis. This parasite is swallowed in the larval form, and 

 undergoes sexual changes in the intestine, at first producing intestinal 

 trichinosis, which represents the first phase in the development of the 

 disease. 



The trichinte breed rapidly. The embryos penetrate into or are 

 directly deposited in the blood-vessels, which convey them to all parts of 



Fig. 44. — Gravid segmeut of beef- 

 measle tapeworm [Tcenia sagi- 

 nata), showing lateral branches 

 of the uterus, enlarged. (Stiles, 

 Annual Report U.S.A. Bureau 

 of Agriculture, 1901.) 



Fig. 45. — Egg of beef-measle tapeworm 

 {Tcenia saginata), ^\•ith thick egg-shell 

 (embrvophore"), containing the six- 

 hooked embryo (oncosphere), enlarged. 

 (After Leuckart.) 



the body, thus setting up the second phase of the disease, known as 

 muscular trichinosis. 



Trichinosis as a disease has long been recognised. Peacock in 1828 

 and J. Hilton in 1832 mentioned the existence of the cysts of trichinae ; 

 Owen in 1H35 gave the name of Tridiina spiralis to the parasites con- 

 tained in the cysts. Trichinosis being common in Germany at that time, 

 A'irchow and Leuckart undertook its investigation, but mistook other 

 nematodes of the intestine for the Trichina spiralis. In 1847 Leydy 

 recognised that trichinosis occurred in American pigs. 



In 1860 Zenker found muscular and intestinal trichinosis on post- 

 mortem examination of a girl who had been suspected of suffering from 

 tyi)hoid fever, and a carefully conducted inquiry revealed the fact that 



